Some Elephants Are Evolving to Lose Their Tusks

Some elephants have developed a genetic trait that allows them to go tuskless. Jonathan Pledger/Shutterstock

Poachers are having more of an effect on the elephant population than simply diminishing it.

Unpublished findings from two different researchers have determined that tusklessness is on the rise among female African elephants, particularly those that are descendants of elephants that survived civil wars and poaching efforts.

Going tuskless

Poachers focus on male elephants' tusks first since they're larger and heavier than those of females of a comparable age. Eventually, poachers will then turn to older females. The result, according to Joyve Poole, an elephant behavior expert and founder of Elephant Voices, is a tuskless female population.

Poole compiled the first data set, which was reported by National Geographic on Nov. 9. Poole's research focused on the elephants in Mozambique's Gorongosa National Park, a population that once exceeded 4,000 and is now in the triple digits following a 15-year civil war. Of the 200 known adult females that survived the war, just over half of them are tuskless. Of the generation born after the war's conclusion in the mid-1990s — basically any elephant under the age of 24 — about 32 percent of the females are without tusks.

Poole also found that female elephants without tusks in South Africa have experienced an extreme uptick. Ninety-eight percent of the 174 females in Addo Elephant National Park were reportedly tuskless as of the early 2000s.

A tuskless elephant near a calf with tusks
Researchers aren't sure what causes tusklessness as a trait in female elephants. Peter Betts/Shutterstock

The second data set comes from elephant populations in Tanzania. Josephine Smit, a researcher with the Southern Tanzania Elephant Program and a doctoral candidate at the University of Stirling, in Scotland, found that about 35 percent of elephants 25 years or older in Ruaha National Park are tuskless, while 13 percent of those younger than 25 are without tusks. Like areas in Mozambique and South Africa, Ruaha National Park was the site of heavy poaching in the 1970s and 1980s.

To put all this in context, tusklessness occurs in around 2 to 4 percent of females in unpoached populations. It's possible, then, that tusklessness as a trait is being passed down to better ensure survival.

Exactly how this is happening is still a mystery. Tusklessness occurs mainly in females — Poole says she's only ever seen three or four tuskless males in her entire career, and none of them were in Gorongosa — so that would seem to indicate that the trait is tied to the X chromosome. But if it is, than we would probably see a much larger population of male elephants without tusks.

What tusklessness means

A close up of an elephant's tusks near a tree
Elephants use their tusks to scape bark off trees. Jo-anne Hounsom/Shutterstock

While they're little more than overgrown teeth, elephants use their tusks in a variety of ways, including digging for water and debarking trees, according to National Geographic.

Ryan Long, a behavioral ecologist at the University of Idaho, and a team of geneticists and ecologists started tracking six adult females, three with tusks and three without, from different herds back in June. In addition to the GPS trackers, Long and his colleagues took blood and stool samples. They will monitor the elephants for a few years (or until the trackers give out) to see how they move, eat and how their genomes are shifting.

Smit has, anecdotally, noticed some changes in behavior.

"I've observed tuskless elephants feeding on bark, and they're able to strip bark with their trunks, and sometimes they use their teeth," she said to National Geographic. The elephants may be eating from trees that are easier to strip, or trees that have already be stripped a bit. Smit also suggests that other elephants may simply help out their tuskless brethren.

The lack of tusks could also have an impact on other wildlife. Some lizards, for instance, prefer to make their homes in trees that elephants have stripped or knocked over, while other animals rely on the tusk-dug water holes for nourishment.

Still, it may be some time before know the full extent of what this genetic trend means for elephants and their environment.